Fishing may be done using a variety of techniques and equipment. Some types of recreational fishing are done from boats. Such boats may be powered by gasoline engines or electric motors depending on the type of fishing that is being done. One particular type or style of fishing is trolling with the use of an electric outboard motor. Electric trolling motors (ETM) are preferred for certain trolling operations because of a lower power ratio (compared to gasoline), less disturbance to the shallow waters being fished, and their small size.
A rudder is a steering device usually rectangular in shape and frequently comprises a metal blade mounted behind a propeller and quite close to it. A rudder is used to attain and maintain a desired heading. The force necessary to accomplish this is developed by dynamic pressure against the flat surface of the rudder. Various types of rudders have been suggested for use in trolling to aid in steering and to help maintain direction in the water but most of these have been confined to use with gasoline engines.
For example, U.S. Pat. No. 3,991,700 to Cleary teaches a rudder attachment for a gasoline trolling outboard motor where the motor has a gear case, a propeller and a horizontal cavitation plate. The rudder is mounted in an upright position behind the propeller by attachment to the cavitation plate.
U.S. Pat. No. 3,828,718 to Jolin discloses an auxiliary rudder attachable to a gasoline outboard motor to give the person running the boat full control of his steering at all times, including during trolling operations. The rudder is a flat plate 8 inches by 8 inches square with mounting structures including shims, a bracket, and a tension coil spring. Although not expressly stated, the elongated mounting bracket is intended to be placed around an elongated portion of the streamlined motor housing and the rudder supported by a cavitation plate or other horizontal member of the housing member.
U.S. Pat. No. 3,285,219 to Linsley shows a rudder and stabilizer attachment for gasoline outboard motors which is mounted rearwardly of the propeller.
U.S. Pat. No. 3,687,101 to Linsley teaches a marine rudder for use on a gasoline outboard or inboard engine. The rudder is disposed mostly above the cavitation plate and makes straightening of the rudder easier at high speeds.
While a variety of rudders have been suggested for various uses, these rudders are not designed for use with electric trolling motors. A rudder for an electric trolling motor must have a sufficient surface area to create water resistance but sufficiently streamlined to avoid drag hindering the limited power of the electric motor. The mounting of a rudder on an electric trolling motor cannot be done in the same way as for a modern gasoline engine. Virtually all electric trolling motors are provided with a smooth, circular motor tube or shaft connecting the submerged motor and propeller assembly with an operator control unit. In contrast the gasoline outboard motors are generally provided with an elongated, streamlined housing and a cavitation plate structure or other horizontal member which can be used to support and secure a rudder. Thus it is an object of the present invention to provide a rudder for use with an electric trolling motor and mountable to the shaft thereof. It is also an object of the present invention to provide a rudder for an electric trolling motor which aids in keeping a boat on course in rough water, strong winds and/or strong currents. A further object of the invention is to provide a rudder for an electric trolling motor which allows trolling at low speeds in shallow water. It is yet another object of the invention to provide a rudder for an electric trolling motor which reduces problems of oversteering. It is a further object of this invention to provide a safe and light rudder with reduced drag for an electric trolling motor. It is yet another object of the invention to provide a streamlined rudder and mounting for an electric trolling motor which reduces the occurrence of cavitation. Yet another object of the invention is to provide an electric trolling motor rudder which is mounted so as to counterbalance and reduce the motor side thrust component. It is yet another object to provide an electric trolling motor rudder which is symmetric about a horizontal plane to allow the rudder to be used with either clockwise turning or counter-clockwise turning propellers. It is yet another object of the invention to provide an improved, non-slip mounting for securing a rudder to the circular shaft of an electric trolling motor. These and other objects of the invention will be apparent from the following description of the invention.